Chapter 26

1. Copper oxides are a product of the oxidation of copper that often form on the inside of copper pipes transporting water and serves to protect the pipes against corrosion. They are toxic. At a pH above 8, these oxides are virtually insoluble in water. As the pH of the water flowing drops below 7, the solubility of these oxides increases, and the layer begins to dissolve. Based on this knowledge, and the data collected in your lab, what implications does this have on toxic metal pollutants or other pollutants in our drinking supply when the water flowing is acidic? Would this problem become better or worse if the water flowing through the pipes was hot? 2.  The chemical obtained from red cabbage that acts as a pH indicator is a pigment called anthocyanin.  Based on your results, do you think anthocyanin is a useful indicator?  Why or why not?

Describe the blood hydrogen carbonate buffer system. What happens when blood acidity rises? Show the equation. What happens when the blood becomes more alkaline? Show the equation. Distinguish between strong and weak acid. List some clinical uses of these acids and write equations for their dissociation in water. Did you find any of these to be a challenge? Why or why not?

Calculate the concentration of SCN in each of the following standard solutions. Use 0.0500 M Fe3+ and 0.00200 M SCN-   a. 1.00 mL SCN- + 5.00 mL Fe3+ (final volume = 10.00 mL)   b. 2.00 mL SCN- + 5.00 mL Fe3+ (final volume = 10.00 mL)   c. 3.00 mL SCN- + 5.00 mL Fe3+ (final volume = 10.00 mL)   d. 4.00 mL SCN- + 5.00 mL Fe3+ (final volume = 10.00 mL)

What process is responsible for the increase in the total negative charge as soil pH increases?    a. Deprotonation   b. Protonation   c. H+ bond formation   d. Dehydration reaction

References Chapter 8 EOC What is the pH of a boric acid buffer solution containing mol/L of boric acid, , and mol/L of its conjugate base? The of boric acid is .

What buffers are in blood plasma and how are acidosis and alkalosis involved in the changes of pH balance?

Answer question numbers 18, 19 & 20

Each row of the table below describes an aqueous solution at 25 °C. The second column of the table shows the initial components of the solution. • Use the checkboxes in the third column to explain the type of the initial solution. The fourth column describes a change in the solution. • Use the fifth column to predict how the change in the solution will change its pH. solution initial components initial type (check all that apply) effect of change on pH change (check one) A H₂O 0 000 0 acidic pH higher basic neutral acidic add K C104 pH lower B 80 H₂O, H Br basic neutral add Na Br O O acidic C H₂O, H Br basic neutral add NaOH pH lower acidic pH the same pH higher D H₂O basic add KOH pH lower neutral pH the same pH higher pH lower pH the same pH higher pH the same

Pseudogout, a condition with symptoms similar to those of gout (a condition that results in joint swelling and pain), is caused by the formation of calcium diphosphate (C22P207) crystals within tendons, cartilage, and ligaments. Calcium diphosphate precipitates out of blood plasma when diphosphate levels become abnormally high. Part A If the calcium concentration in blood plasma is 8.8 mg/dL and Ksp for calcium diphosphate is 8.64 × 10¬13, what minimum concentration of diphosphate results in the precipitation? Express your answer in moles per liter to two significant figures. [P2O,4] = M

Explain the bicarbonate buffer system

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CHM 731A Lab 9 - 2021SP Test for sodium chloride: to approximately 1 mL of NaCl solution, 1-2 drops of silver nitrate solution are added. The test results are presented in the table Reference tests. Reference tests Test Positive Result (color) Negative Result (color) Chloride white colorless Glucose Starch

Part C - Acid-base and solubility equilibria 1. Rinse 4 regular size test tubes and a 10 mL measuring cylinder thoroughly with water. Number the test-tubes from 1 to 4 in a test tube rack. 2. Into each of test tubes 1 – 3 put a small amount of solid benzoic acid (put the same amount – about the size of a pea – in each test tube). 3. Add 2 mL (use the measuring cylinder) of water to tube 1 and shake to mix the contents. 4. Add 2 mL (measuring cylinder) of 2 M HNO, to tube 2 and shake to mix the contents. 5. Rinse the measuring cylinder with water, then use it to add 2 mL of 2 M NaOH to tube 3 and shake for about 10 seconds to mix the contents. Rinse the measuring cylinder. 6. Pour about half of the solution from tube 3 into tube 4, than add 2 mL of 2 M HNO3 to tube 4. 7. Allow the test tubes to stand for 2 or 3 minutes then record the appearance of the mixtures in each test tube. 8. Answer the questions on the results page relating to this equilibrium system. Results Test tube…